A simple determination of the halo size from<sup>10</sup>Be/<sup>9</sup>Be data
D. Maurin, E. F. Bueno, L. Derome
Abstract
Context. The AMS-02 and HELIX experiments should soon provide 10 Be/ 9 Be cosmic-ray data of unprecedented precision. Aims. We propose an analytical formula to quickly and accurately determine L from these data. Methods. Our formula is validated against the full calculation performed with the propagation code USINE . We compare the constraints on L set by Be/B and 10 Be/ 9 Be, relying on updated sets of production cross-sections. Results. The best-fit L from AMS-02 Be/B data is shifted from 5 kpc to 3.8 kpc when using the updated cross-sections. We obtained consistent results from the Be/B analysis with USINE , L = 3.8 −1.6 +2.8 kpc (data and cross-section uncertainties), and from the analysis of 10 Be/ 9 Be data with the simplified formula, L = 4.7 ± 0.6 (data uncertainties) ±2 (cross-section uncertainties) kpc. The analytical formula indicates that improvements on L thanks to future data will be limited by production cross-section uncertainties, unless either 10 Be/ 9 Be measurements are extended up to several tens of GeV/n, or nuclear data for the production of 10 Be and 9 Be are improved; new data for the production cross section of 16 O into Be isotopes above a few GeV/n are especially desired.